Alexei N. Krouglov’s lecture examines Kant’s understanding of war in order to clarify, and partly correct, the widespread image of Kant as a straightforward pacifist whose treatise Perpetual Peace anticipates the international order of the twentieth and twenty-first centuries. Krouglov argues that this reception is one-sided: alongside the tradition that reads Kant as a prophetic theorist of peace, there is another line of interpretation—already present in early twentieth-century Russian and European debates—which sees Kant as an intellectual source of later militarization and catastrophic wars. To assess these opposed images, he turns away from Kant’s concept of peace alone and reconstructs Kant’s concept of war, his typology of wars, and his complex, often tension-ridden evaluation of war in law, history, and morality.
Krouglov first maps the main Kantian texts in which war is thematically important. From the legal side, these are above all the Doctrine of Right in The Metaphysics of Morals, the associated reflections on natural right (including the so-called Naturrecht Feyerabend notes), and The Conflict of the Faculties. From the historical and aesthetic side, war appears in the Critique of the Power of Judgment, in the Observations on the Feeling of the Beautiful and Sublime, in the essay Idea for a Universal History and above all in The Contest of the Faculties and The Conjectural Beginning of Human History. Finally, Perpetual Peace combines legal and historical argument. These writings differ in genre and weight: some are programmatic texts intended, in Kant’s own terms, “for all time,” others are occasional pieces or lecture notes tied closely to contemporary events. This heterogeneity already makes a completely uniform doctrine of war unlikely.
The first systematic step is Kant’s general concept of war and his classification of different kinds of war. For Kant, the state of nature between human beings is structurally a state of war, in the sense of a constant threat of violence and outbreaks of hostility. Strictly speaking, however, war in the proper sense is not the violent acts of individuals against one another, but the armed conflict between states. This interstate conflict can itself be viewed in two ways: as a continuation of the state of nature, where war is a regrettable last resort for asserting right by force, or within an already established legal relation—the law of war and peace—where war is at least subject to juridical norms.
Kant’s explicit judgments on war are, taken in isolation, severe. He calls war “the right of the stronger,” “destroyer of all good,” “the greatest evil that can befall the human race,” “the main obstacle to moral progress” and “the grave of the human race.” At the same time, he develops a differentiated typology: punitive war, war of extermination, war of subjugation, war of aggression, offensive and defensive war, and what he calls “patriotic war.” He considers punitive war between independent states impossible in strict right, because punishment presupposes a superior authority, which does not exist between sovereign states; from this he infers that a victor has no right to demand indemnities or to turn a defeated state into a colony whose population becomes serfs. Wars of extermination, aimed at the annihilation of an enemy whose hostility seems without end, are condemned as radically incompatible with any enduring right. Yet it remains significant that Kant illustrates such wars with stereotyped examples (for instance, from conflicts involving “Indians”) that do not fully correspond to historical realities and reveal clear Eurocentric distortions.
Krouglov points out a remarkable absence in the Kantian corpus: Kant hardly ever refers to the Seven Years’ War, which directly affected Prussia and Königsberg and which he personally lived through. Nor does he use examples from modern European warfare; instead, he repeatedly appeals to classical cases such as the Peloponnesian or Trojan wars. Equally revealing is the fact that terms such as “revolutionary war,” “religious war,” or “civil war” do not appear in his published works and Nachlass. This selectivity of examples and concepts shapes Kant’s image of war and may partly explain why his normatively rigorous legal framework remains at a certain distance from the emerging realities of modern mass warfare.
The second main theme is Kant’s treatment of the honorable and the sublime in war, and his account of the historical function of war. On the one hand, Kant insists that war devastates morals and institutions and produces more evil than it removes. On the other hand, he repeatedly links war with honor, courage, and a certain elevation of the human spirit. The defense of the state is for him a matter of honor that can stand higher than life itself, and among peoples he labels “savages,” martial courage is the highest virtue. In patriotic war, where citizens take up arms not for pay or plunder but for the preservation of their political community, Kant sees the possibility that soldiers, once they become citizens again, may develop civic virtues.
In the Critique of the Power of Judgment, Kant famously states that war possesses “something sublime” because it tests and strengthens the character of a people, provided that hostilities are conducted with strict respect for civil rights and legal order. In The Conjectural Beginning of Human History, he describes a different beneficial side effect: fear of war forces rulers to take their populations seriously, to promote culture, strengthen internal cohesion, and develop a certain regard for humanity. As an illustration, Kant refers to China, whose physical security from invasion allegedly correlates with the absence of freedom—a claim that, as Krouglov stresses, reveals both the limitations of Kant’s empirical knowledge and the risks of deriving political judgments from geographical generalizations.
A further step is taken in the famous “Guarantee” chapter of Perpetual Peace, in which “great artful Nature” uses war as an instrument to drive human beings across the globe and into ever denser legal and political relations. War becomes, in this narrative, an indispensable means for nature to realize its teleological aim: a cosmopolitan legal order. Yet Kant adds something here he had not formulated so sharply earlier: nature employs war as a means, but the human species appears in this teleological story almost as a herd of animals that nature drives forward. As humans, Kant insists, we can and should contribute to perpetual peace ourselves; nature’s guarantee only secures that the moral path is not a chimera. This double perspective—nature as quasi-artist and humans as moral agents—sits uneasily with Kant’s own critical strictures; Krouglov notes how difficult it is to reconcile the language of a “great artful Nature” that drives humanity toward its ends with the transcendental thesis that the understanding prescribes laws to nature, not the other way round.
The third focus of the lecture is Kant’s argument against war in The Metaphysics of Morals and in Perpetual Peace, and the internal difficulties of this argument. In the section on public right in the Doctrine of Right, Kant formulates a decisive moral conclusion: practical reason in us pronounces an unconditional veto—“There shall be no war.” Neither between individuals in the state of nature nor between states is war an admissible way of pursuing one’s right. This is one of Kant’s clearest statements against war. Perpetual Peace, written earlier, still combines this normative orientation with a more elaborate historical and teleological interpretation of war and therefore appears less unambiguous.
In the preliminary and definitive articles of Perpetual Peace, Kant assembles a heterogeneous set of arguments for peace. There are juridical and moral reasons, but also geographic, economic, and quasi-religious considerations. He stresses the finitude of the earth’s surface, the growing commercial interdependence of peoples, the role of public debt, and the “spirit of commerce” that allegedly cannot coexist with war and thus compels states to pursue peace. For Krouglov, this multiplicity of motives has a heteronomous character: arguments of statecraft and prudence are interwoven with moral and legal arguments, without always being clearly distinguished.
A central republican argument, anticipating later democratic peace theories, is that citizens themselves must consent to war. Because they would personally bear the costs—taxes, devastation, death—they are presumed to be far more reluctant to approve war than monarchs who can treat war as a “pleasure trip” without suffering directly. Kant thus expects that in a genuine republic, wars will be rare. Krouglov regards this expectation as overly optimistic, especially in light of the experience of the world wars and the power of nationalist enthusiasm and propaganda. The assumption that citizens will reliably reject war once they calculate its costs has not been confirmed by subsequent history; economic incentives and war profits complicate the picture.
Krouglov also draws attention to Kant’s treatment of soldiers. In Kant’s legal writings, the soldier appears as a “mere instrument” or “machine” in the hands of the state, an example of usefulness as a means rather than as an end in itself. Kant even remarks that a simple, unreflective soldier can be very useful to his officer. While Kant later favors a republican constitution with a citizen militia rather than a professional standing army, he does not fully confront the problem of those citizens who, under republican procedures, vote against war but are then bound by the majority decision to fight a war they consider unjust. Nor does he systematically explore the ethical status of obedience in such cases.
A further difficulty arises in Kant’s discussion of preventive war in the second appendix to Perpetual Peace. He rejects the idea that small states may pre-emptively attack a rising neighboring power they fear, even if that power has not yet committed any aggression. His argument, however, proceeds largely in terms of prudence: such a maxim, once publicly declared, would “frustrate its own purpose,” since the stronger power would attack first. Here “injustice” seems to be defined less as a violation of right and more as a failed strategy. Combined with Kant’s comparatively indulgent attitude toward the hypocrisy of states that cloak their wars in legal pretexts, this line of reasoning risks blurring the contrast between offensive and defensive, preventive and aggressive war.
Kant’s well-known sixth preliminary article, which forbids violent interference in the constitution and government of another state, leads Krouglov to the contemporary debate on “humanitarian interventions” and “wars for human rights.” Historically, the article was read by some as a defense of the French Revolution against foreign intervention. Later, especially in twentieth-century commentaries, the same passage has been reinterpreted as implying that “republics” (or democracies) may, or even should, intervene in non-republican states to promote individual rights—an interpretation Krouglov considers deeply problematic. He recalls early nineteenth-century critics such as Johann Nikolaus Tetens, who warned that wars waged in the name of higher aims such as civilization, freedom, and humanity could be even more dangerous than classical religious wars, because they legitimize forcing one’s own conception of the good on others who do not share it.
Finally, Krouglov returns to the broader systematic question: how do these dispersed and sometimes contradictory reflections on war relate to Kant’s central critical philosophy? He stresses that Kant is not uniformly at the same theoretical level across all his writings. The three Critiques and some major works of moral and legal philosophy represent a peak; many occasional political and historical essays, including Perpetual Peace, do not reach the same systematic rigor. If Perpetual Peace had been published anonymously, he suggests, it is doubtful whether it would occupy its current place in political philosophy; its prominence is inseparable from Kant’s name and from his fundamental work on the moral law and transcendental critique.
Krouglov’s overall conclusion is cautious. Kant’s philosophy does offer powerful resources for criticizing war: the moral veto of practical reason, the idea that human beings must never be treated merely as means, the republican requirement that those who bear the costs of war must consent to it, and the legal principle that no state may be eliminated as a moral person. At the same time, Kant’s historical and teleological reflections on the “great artful Nature,” his idealization of certain forms of war as honorable or sublime, his silence on revolutionary, religious, and civil wars, and his dependence on the relatively limited experience of eighteenth-century warfare all introduce tensions and blind spots. Any contemporary appeal to Kant against war must therefore distinguish carefully between those elements of his thought that retain normative force and those that reflect the constraints, assumptions, and illusions of his own political world.
Simon Gros 
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